Receiver for space signaling systems.



No. 883,437. PATENTBD MAR. 31, 1908. L. D. WILDMAN. RECEIVER FOR SPACE SIGNALING SYSTEMS.

APPLICATION FILED JULY 24.1906.

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UNITED STATES LEONARD D. WILDMAN, OF SAN FRANCISGQ, CALIFORNIA.

RECEIVER FOR SPACE SIGNALING BYS'IEXB.

B pecification ofLetters Patent.

Batented March 31, 1908.

Application filed July 24, 1906. Serial No. 321,591.

To all whom it may concern:

Be it known that I, LEONARD D. WILD- MAN, a citizen of the United States and captain in the United States Army, residing at San Francisco, in the county of San Francisco and State of California, have invented certain new and useful Improvements in Receivers for Space Signaling Systems; and I do hereby declare the following to be a full, clegr, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

Thisinvention relatesto improvements in devices for detecting electrical oscillations or Hertzian waves, and is designed especially for use as receiving apparatus for so-calledwireless telegraphs or other space signaling systems.

The primary object of this invention is the production of an Imperfect contact detector of the above character which shall be highly sensitive to received electrical oscillations, but responsive:to the smallest extent possible to vibrations due to the unsteady foundation upon which the apparatus may be placed, to vibrations due to concussion, or to other causes not intended to affect the said detector, and which shall be self-restoring after the passage of the signaling impulses. This tendency torespond to extraneous vibrations has heretofore been one of the chief faults of imperfect contact receivers, causing sequent oxidation of contacts to produce the insulating film.- In my receiver this insulat ing film is produced by the oil, which, being under pressure, instantly passes between the contacts after the passage of the signaling impulse.

A third difficulty has been that with a con,- tinued passage of a number of sparks or signals, there has been a tendency to minute,

partial welding of the two contacts, and my.

invention overcomes this difficulty and intacts.

the contacts.

,A further object of my invention isthe production of a simple and efliclent callsup device which is attainable from thefactthat by means of my improved detector, I am ena 1 stantly, restores the separating film between imperfect contact devices for-"the purposes I herein named, in that the movable contact or contacts, or both fixed and movable contacts, if there be a fixed contact, are either wholly or partly immersed in a li uid of such a nature that the film between t econtacts will be readily punctured by the Hertzian waves, while the bodv of the liquid will take up and dissipate oscillations other than electrical oscillations imparted to the liquid and which are not intended to operate said contacts and-which will alsoactto damp "the movement of the movable contact or conoil, which has een used'with great success.

Another improvement in some forms of this detector is the additional pressure ofair or a gas, which may be added to the top or any portion of the oil, by means of an air pumpor other device, for giving pressure,

the purpose of whichis to create an additional head upon the oil, facilitating uick Theliquid which best fulfils theforegoing requirements should fiow'freely and be of an insulatin nature, such for. example,

closure of the puncture of the film of oi between the contacts, if there be any such film. The specific arrangements by which the. principle of my present invention may be carried out are many, and I shall not herein attempt to describe them all. For thepurposeof illustrating the principle of myinvention, however, I have herein shown and described three simple specific forms thereof in the accompanying drawings, in wh1ch:

Figure 1 is a semi-diagrammatic view of a space signaling receiving station embodying one form of mysaid invention; Fig. 2 along1- tudmal cross sectional view of a filings coherer embodying my said invention, andv Fig. 3 a setin-diagrammatic view of a space signaling receiving station embodying another form of my said invention.-

Referring first to the form of the invention shown in Fig. 1 of the accompanying drawings, 1 .represents the antenna or vertical Wire, and 2 an earth connection which may or may not include the condenser 3. Ohviously a suitable artificial ca acity may be substituted for the earth. onnected between the antenna and the connection 2, are the detector contacts 4 and 5. While I do not confine my invention to the use of any specific material for these contacts, I prefer to make the contact 4 of silver or platinum and the contact 5 of graphite. The contact 4 in the case shown is mounted upon a resilient arm 6 of conducting material, which ma be a cop er spring secured at its lower en to an insu ating base 7 made fast within a suitable receptacle 8, which latter is preferably of glass, hard rubber or other insulating material. Any other suitable support 'for the contact 4 by which the same may be held subject to movement by received electrical oscillations may be employed. The said contact 4 is in electrical connection with the vertical wire 1, as for example, through conductor 9 andbindin post 10.

The contact 5, whio in this case is the stationary contact, is mounted upon one end of a s rew 11 supported by and arranged to travel in a stationary supporting bracket 12, the said screw passing through a suitable stutting box 13 in receptacle 8 and provided at its end outside of said receptacle with a milled or other suitable head 14. The contact 5 is in electrical connection with the earth connection 2 through the screw i1, bracket 12, conductor 15 and the binding ost 1.6.

The receptacle 8 contains a iquid 17, ureterably oil, which, in the case shown, entirely covers or subn'ierges the contacts 4' and 5. The contact 5 may be adjusted so as to make imperfect electrical contact with the contact 4 or be entirely out of electrical engagement therewith. The apparatus will Work well in either case.

The receptacle 8 maybe made air tight and a valve 8 provided in its top through which air or gas may be pumped into the receptacle and additional pressure thereby caused on top of the fluid 17. This extrapressure improves the action of the device.

For the purpose of receiving signals i may connect in shunt around the contacts 4 and 3 a local circuit which may include a source of current 18, preferably a closed circuit or gravity-battery, telephone receiver or other translating device 19, an indicating instrument 20, which in the case shown is a millimeter, and a rheostat 21 for varying the electro-motive force of said circuit, -the latter being electrically connected by conductor 22, through binding post 23 and conductor 34 to bracket 12. in case a millimeter is employed, as stated, it will be found convenient to. use one with a large scale.

With a given adjustment of the contacts and 5, the indicating instrument 20 may be sea-rev made to normally stand at a certain scale indication. For example, with a millimeter which I have used, reading to 2 milliamperes over the entire scale, the needle normally stands at 4/10 with a given battery.

When signal oscillations are received on the antenna, coherence between contacts 4' and 5 becomes apparently better and the pointer of the indicating instrument moves say to a position where it indicates 5/10, but not with sufficient damping to indicate dots and dashes. The movement of the millimeter pointer, however, indicates the reception of e-ectric signaling impulses.

Since the coherence of the contacts 4 and 5 will differ with the strength of the signals received and since the deflection of the pointer of the indicating instrument will vary with the varying degrees of such coherence, it is possible with this arrangement and with a given set of stations, to tell just which station is sending. For this purpose the scale of the indicating instrument may be calibrated to indicate the different stations. Obviously in such a case the antenna would not be attimed. One of the advantages of this arrangement is that one can always set or adjust the im erfect contacts by bringing the pointer of t 1e indicating instrument back .to a given scale division, such for example as to the 4/10 division hereinbel'ore mentioned, when no signals are coming in. One can, therefore, by a mere glance at the indicating instrument tell whether the apparatus is properly adjusted.

It will be obvious that with the contacts 4 and 5 subject to vibration by influences other than the signaling oscillations, such an arrangement would fail. This difhculty, how ever, is entirely overcome in my present invention by the action of the liquid in the re ceptacle 8, which action I believe to be the following: The liquid (preferably oil) absorbs and dissipates such vibrations as may be imparted to it from extraneous sources, and therefore either entirely prevents the force of such vibrations from ever reaching the movable contact or lessens the force of such as do reach it, and in the latter case acts to so damp the movement of the movable contact as to render such movement either nil or inappreciable. There may also be other mechanical or physical reasons why the liquid bath improves the action of the detector.

The telephone receiver 19 may be used for the reception of regular dot and dash or other signals intended for the station. if, however, the local shunt circuit is used merely to operate the call-up device, the telephone receiver may obviously be omitted.

In Fig. 2 I have shown a filings coherer constructed according to my invention. in which 25 indicates an ordinary coherer glass tube, 26 the coherer particles between contacting plates 27 and '23. This cohercr differs from those hitherto used in having the particles 26 submerged in a bath of oil 29, or other suitable freely flon ing insulating liquid contained in the tube 25. The contact established by such a coherer is practically constant, as may be shown by a galvanometer connected in circuit therewith. With the contacts not submerged, the deflection of the galvanometer fluctuates perceptibly, while with the contacts submerged, it remains practically constant. The hath not only takes up vibrations, but keeps the contacts in good conditions and this is true in all forms of the invention herein described. The coherer, Fig. 2, may also be provided with a valve 25, through which air and gas may be pumped into the coherer to force pressure on the fluid 29.

In Fig. 3 I have shown another specific arrangement of apparatus embodying my invention. In this form of the invention I employ a receptacle 30 which may be substantially the same as the receptacle 8, and in this receptacle is laced a,li uid 31 which may be the same as iquid 17, t at is, a preferably freely flowin liquid such as Oll or other liquid having t e necessary'properties. A valve 30 having'a similar function to the valve 8 may be connected to a. compression pump 50, for the purpose of increasing the pressure of the liquid in the receptacle.

For the detector contacts I employ a needle 32 of magnetic metal and a preferably very hard smooth graphite plate 33. The plate .33 maybe supported in any suitable position, in order to give more or less surface of contact with, the needle preferably inclined as in the case shown,.by an extended pole piece 34 of a magnet 35, to which pole piece the said plate ma be secured in any desired way. The need e contact 32 is movably suspended from an insulating support 36, which is also secured'to said ma net and may or may not include ablade 32 or additional dumping. The coils ofthe magnet 35 are connected by flexible conductors 37 to suitable binding posts'38 in circuit with a source of current 39, preferably aclosed cir cuit battery, and rheostat 40.

Theanag'net 35, to

or other resilient suspension 41 from a suitable rigid support 42, said magnet and con- I the attraction of the said magnet on the needle 32 may be varied, and by this means a very delicate and efficient adjustment of'- the contact '32 relative to the contact 33 may be effected.

The contact 32, in the case. shown, is electrically connected by flexible conductor 43 through a binding post 44 to theantenna 1,

ther with. the detector contacts are suspen ed by means of spring while the contact 33 is electrically connected by a flexible conductor 45 through binding post 46 to the earth wire), which latter may or may not be connected to earth through condenser 3. In this case the local shunt circuit around the detector contacts may contain the same parts as in the arrangement illustrated in Fig. 1. In Fig. 3, however, I have shown. a reflecting galvanometer 47 as replacing the millimeter 20. In this case the calling stations may be indicated by the position of a reflectio on a scale or screen. The galvanometer 47, however, should not be too sensitive.

By suspending in the liquid 23 the whole self contained device comprising the magnet and'contacts carried thereby, the liability of said contacts to become affected by extraneous vibrations other than received electrical oscillations, is greatly diminished and is further diminished by making the suspension resilient.

I have had devices of this character in adjustment for many days at a time and have found that the reading of a millimeter connected in circuit therewith at the end of the time to be exactly the same as when the instrument was first adjusted and this in spite of blows by means of.a hammer given a table on which the said ap aratus was supported, and also in spite o ordinary jars or vibrations which naturally occurred in a' ortable house in which the ap aratus was ept.

Having described severa specific forms of apparatus embod in my invention of which ot er modifications, what normally separating said contacts but permitting contact when said oscillations are received on said conductor, said means restablishing" said separation after the passage of each oscillation, and means to damp the movement of said surfaces.

2. Receiving apparatus for space signaling by 'Hertzian oscillations, comprising a conductor to be set in a state of electrical excitation by said oscillations, relatively movable conducting surfaces in close proximity to each other, means separating said contacts and operated upon by said oscillations received on said conductor, establishing an electrical contact, said means restablishing said separation after' the passage of each oscillation, and damping means surrounding the contact portion of said conducting surfaces.

3. Receiving apparatus. for space signaling by Hert'zian oscillations, comprising a conductor to be set in a stateof excitation by said oscillations, conducting surfaces in close proximity to each other and relatively movable, a film separating said surfaces and adapted to be puncturedby the passage of said oscillations received on said conductor, and a non-conducting bath in which said conducting surfaces are submerged which reestablishes said separating film.

4. Receiving apparatus for space signaling by Hertzian oscil ations, comprising a conductor to be set in a state of' excitation by said oscillations, conducting surfaces in close proximity to each other and relatively movable, a self-restoring liquid film separating said surfaces and adapted to be punctured by said oscillations received on said conductor, and an oil bath in whichsaid conducting surfaces are submerged. I

5. Receiving apparatus for space signaling by Hertzian oscillations, comprising an antenna, relatively movable conducting surfaces located in close proximity to each other, a self-restoring film separatin said surfaces and adapted to be punctured y oscillations received on said antenna, a bath of non-conducting liquid in which said conducting surfaces are submerged, and means for placing said liquid under compression.

6. Receiving apparatus for space signaling by Hertzian oscillations, OOIIIPIlSlIl an an tenna, av capacity, relatively mova le con'-" ducting surfaces normally in imperfect electrical contact between said antenna andsa d capacity, a'bath of non-conducting liquid in 'which said conducting surfaces are submerged, and means for placing said liquid.

under pressure.

7. Receiving apparatus for space signaling by Hertzian oscillations, comprisin an antenna, a capacity, relatively mova le conducting surfaces normally in imperfect electrical eontact between said antenna and said capacity, a bath of oil in which said conducting surfaces are submerged, and means for placing said oil under pressure.

8. Receiving a paratus for space signaling by Hertzian osc lat'ions, comprising an antenna, conducting surfaces normally inimperfect electrical contact and relatively mov able, a non-conducting mobile liquid normally interposed between said conducting surfaces, and means for placing said liquid under pressure, whereby'said contacts will be brought into-contact during the passage of said oscillations and immediately separated by said liquid after the passage of the oscillations.

9. Receiving a paratus for space signaling by Hertzian oscl lations, comprisin a conductor to be set in a state of electrica excitation by said oscillations, conducting surfaces located in close proximity to each other and relatively movable, means interposed between said surfaces adapted to be punctured only during the passage of said oscillations received on said conductor, a bath of mobile non-conducting substance, and means for elastically suspending said conducting surfaces therein.

10. Receiving apparatus for space signaling by I-Iertzian oscillations, comprising an antenna, conducting surfaces normall in imperfect electrical contact and relative y movable, means interposed between said surfaces adapted to be punctured only during the passage of said oscillations received on said antenna, a bath of oil, and means for yieldingly suspending said contacts in said bath.

11. Receiving apparatus for space signaling by Hertzian oscillations, comprising. a conductor to be set in a state of excitation by said oscillations, conducting surfaces located in close proximity to each other and relatively movable, means interposed between said surfaces adapted to be punctured during the passage of said oscillations received on said conductor, means for damping the movement of said surfaces, and magnetic means for adjusting the normal relative positions of said surfaces.

12. Receiving apparatus for space signaling by Hertzian oscillations, comprising a conductor to be set in a state of excitation by said oscillations, conducting surfaces located. in close proximity to each other and relatively movable, means interposed between said surfaces adapted to be punctured during the passage of said oscillations received on said conductor, a bath of mobile non-conductin liquid in which said surfacesare submerge and magnetic means for adjusting the normal relative positions of said surfaces.

1-3: Receiving apparatus for space signaling. by Hertzian oscillations, comprising a conductor to be set in a state of excitation by said oscillations, relatively movable conducting surfaces yieldingly held in close proximity to each other in circuit with said conductor, a bath of non-conducting liquid in which said contacts are suspended, magnetic means for adjusting the normal relative positions of said surfaces, and for placing said iquid under pressure.

14. Receiving apparatus for space signaling by Hertzian oscillations, comprising an antenna and a capacity, relatively movable conducting surfaces normall in imperfect electrical contact between said antenna and said capacity, a magnet to adjust the normal relative 'osition of. said surfaces, a bath of oil, yielding supporting means for suspending both said magnet and said conducting surfaces in said bath, one of said'surfaces being normally attracted towards the other by said magnet, and means to adjust the strength of the said magnet.

15. Receiving apparatus for space signaling by He'rtzian oscillations, comprising an antenna and a capacity, relatively movable conducting surfaces normall in imperfect electrical contact between said antenna and said capacity,-a magnet to adjust the normal I of oil, means for lacing said oil under pres relative position of said surfaces, a bath of nonconductmg liquid, ielding supporting means for suspending bot said magnet and said con ducting surfaces in said bath, one of said surfaces being normally attracted towards the other by said magnet, and means to adjust the strength of said magnet.

'16. Receiving apparatus for space signaling by Hertzian oscillations, comprising a conductor to be set in a state of excitation by said oscillations, conducting surfaces in close proximity to each other and relatively mov-' able, a self-restoring liquid film separating submerged, means for said surfaces and adapted to be punctured by said oscillations received on said conductor, means to damp the movement of said surfaces, and a deflection instrument connected in shunt around said surfaces and ada ted to indicate the adjustment of the con ucting surfaces by the amount of the deflection.

17. Receiving apparatus for space signaling by Hertzian oscillations, comprising a conductor to be set in a state of excitation by said oscillations, relatively movable con-. ducting surfaces in closeproximit to each other andin circuit with said con uctor, an oil bath in which said conducting surfaces are (placing said oil bath under pressure, and a efiectlon instrument connected in shunt around said surfaces and ada ted to indicate the relative position of sai( surfaces by the amount of the deflection.

18. Receiving apparatus for space signaling by Hertzian oscillations, comprising an antenna, relatively movable conducting. surfaces normally 1n 1m erfect electrical contact and in circuit wit said antenna, a bath a conducting surfaces normally sure, means yiel lngly suspending said contacts in said bath, and a deflectlon instrument connected in shunt around said surfaces and adapted to indicate stations calling.

19. Receiving apparatus for space signa ing by Hertzian oscillations, comprising an antenna and a capacity, relatively movable in imperfect electrical contact between sald antenna and said capacity, a magnetto adjust the normal relativeposition of said surfaces, a bath of movable non-conducting liquid, yielding supporting means for suspending both said magnet and said conducting surfaces in said bath, one of said surfaces being normally attracted towards the other by said magnet, means to adjust the strength of the said magnet, and a deflection instrument conne'cted in shunt around said surface and adapted to indicate the stations calling by the amount of the deflection.

20. Receiving apparatus for space signal-' ing by Hertzian oscillations, comprising an antenna, conducting surfaces relatively movable by oscillations received on said antenna and located in close proximity to each other, a circuit including an indicating instrument connected in shunt around said surfaces, and

means actin Y upon said surfaces to maintain 

